The use of a collar to attach the pump to a selected closure is a well known expedient in the art. Typically, such collars clamp the top wall of the closure between the lower periphery of the collar on the one hand and an external flange of the pump body on the other hand. Thus, the pump and closure form a complete assembly that can be threaded onto the neck finish of the particular container with which the pump is to be utilized.
Closures are available in a myriad of sizes, shapes and wall thicknesses. Yet it is desirable that one pump fit all varieties. Since the collar of the pump is designed to remain a standard distance from the flange of the pump body for all closures, regardless of their wall thickness, it becomes essential to have some way of accommodating the additional space required by some closures without sacrificing a tight fit on those closures of lesser thickness. Thus, in pumps such as shown in Clevenger et al. U.S. Pat. No. 3,500,761 "Control Valve for Hand Pumps" owned by the assignee of the present invention, there is a yielding or flexing of the collar in some weakened area thereof when the collar is clamped against a greater than normally thick closure with which the pump is associated. A relatively thin web 64 of the collar 16 on the pump in the aforesaid patent provides the necessary flexure.
In some instances, however, flexure in that area cannot be tolerated. For example, in pumps having plungers that can be locked in the "down" position for shipment or storage, the relationship and fit of interengageable locking components of the collar and the plunger can be quite critical to successful operation. Thus, it is essential that no flexure and relative movement of the locking components of the collar occur relative to the cooperating components of the plunger. Rather, both sets of components need to be substantially isolated from the give-and-take of the collar as it compensates and accommodates for the various thicknesses of closures on which the pump is installed.